Rolling type vehicle

ABSTRACT

A rolling vehicle includes a pair of left and right front wheels and a pair of left and right arm members swingably supported by the vehicle body on inner sides in the transverse direction and which support the left and right front wheels in a steerable manner on outer sides in the transverse direction. As viewed from the direction along the axis of a support shaft which supports the left and right arm members on the vehicle body, the base portions of the left and right arm members rotatably supported on the vehicle body side overlap with each other, whereas the swinging center axis of the base portion of the left arm and the swinging center axis of the base portion of the right arm, of the base portions of the left and right arm members, are out of alignment with each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to JapanesePatent Application No. 2015-024459 filed Feb. 10, 2015 the entirecontents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rolling type vehicle.

2. Description of Background Art

Rolling type vehicles are know that include a pair of left and rightfront wheels and in which a vehicle body is capable of lateral swinging,or rolling. See, for example, JP-T-2003-535742 A. The rolling typevehicle disclosed in JP-T-2003-535742 A includes a pair of left andright front wheels, a pair of left and right cross bars for swingablysupporting the left and right front wheels and a rocking lever whereinleft and right outer end portions are connected to the left and rightcross bars through shock absorber struts, respectively. The axes offulcrum pins of the pair of left and right cross bars and the axis of apin of the rocking lever are disposed on the same plane.

In the configuration wherein the axes of the fulcrum pins of the leftand right cross bars and the axis of the pin of the rocking lever aredisposed on the same plane, however, the positions of the axes are setat predetermined positions, which limits the degree of freedom oflayout. In addition, there is a limitation to enlargement of the lengthof left and right arms.

SUMMARY AND OBJECTS OF THE INVENTION

Accordingly, it is an object of an embodiment of the present inventionto enlarge the length of left and right arms while enhancing the degreeof freedom of layout, in a rolling type vehicle which has a pair of leftand right front wheels and in which a vehicle body is capable ofrolling.

As a solution to the above problem, according to an embodiment of thepresent invention, there is provided a rolling type vehicle (1) having apair of left and right front wheels (2L, 2R) and having a vehicle body(1A) capable of rolling. The rolling type vehicle (1) includes a pair ofleft and right arm members (21, 23) supported in a swingable manner bythe vehicle body (1A) on inner sides in a transverse direction forsupporting the left and right front wheels (2L, 2R) in a steerablemanner on outer sides in the transverse direction. In the rolling typevehicle (1), as viewed from a direction along an axis (C2, C3) of asupport shaft (22, 24) which supports the left and right arm members(21, 23) on the vehicle body (1A), those base portions (21 a, 21 b, 23a, 23 b) of the left and right arm members (21, 23) which are rotatablysupported on the vehicle body (1A) side overlap with each other, whereasa swinging center axis (C11) of the base portion (21 aL, 21 bL) of theleft arm (21L) and a swinging center axis (C12) of the base portion (21aR, 21 bR) of the right arm (21R), of the base portions (21 a, 21 b, 23a, 23 b) of the left and right arm members (21, 23), are out ofalignment with each other.

According to an embodiment of the present invention, the swinging centeraxis (C11) of the left arm (21L) is disposed on the right side of alongitudinally extending vehicle body center line (CL), while theswinging center axis (C12) of the right arm (21R) is disposed on theleft side of the longitudinally extending vehicle body center line (CL).

According to an embodiment of the present invention, the left and rightarm members (21, 23) each include an upper arm (21) and a lower arm (23)and the distance (L1) from an axle center (C5) of the front wheel (2L,2R) to a transversely outer end portion (21 c) of the upper arm (21) andthe distance (L2) from the axle center (C5) to a transversely outer endportion (23 c) of the lower arm (23) are different from each other. Inaddition, the swinging center axes (C11, C12) of those ones of the upperarms (21) and the lower arms (23) which correspond to the greater one ofthe distances (L1, L2) are deviated from each other in transversedirection, as viewed from a direction along the axis (C2, C3) of thesupport shaft (22, 24).

According to an embodiment of the present invention, the distance (L2)for the lower arm (23) is set smaller than the distance (L1) for theupper arm (21); and the swinging center axes (C11, C12) of the left andright upper arms (21) are out of alignment with each other, as viewedfrom a direction along the axis (C2, C3) of the support shaft (22, 24).

According to an embodiment of the present invention, the base portion(21 aL, 21 bL) of the left arm (21L) and the base portion (21 aR, 21 bR)of the right arm (21R) are supported by eccentric collars (50) fitted onthe same support shaft (22).

According to an embodiment of the present invention, as viewed from thedirection along the axis of the support shaft which supports the pair ofleft and right arm members on the vehicle body, those base portions ofthe left and right arm members which are rotatably supported on thevehicle body side overlap with each other, whereas the swinging centeraxis of the base portion of the left arm and the swinging center axis ofthe base portion of the right arm, of the base portions of the left andright arm members, are out of alignment with each other. Owing to thisconfiguration, it is ensured that the positions of the swinging centeraxes of the base portions of the left and right arms can be set morefreely within a range in which the base portions of the arm membersoverlap with each other, as viewed from the direction along the axis ofthe support shaft, as compared with the case where the swinging centeraxis of the base portion of the left arm and the swinging center axis ofthe base portion of the right arm coincide with each other as viewedfrom the direction along the axis of the support shaft. As aconsequence, the length of the left and right arms can be enlarged whileenhancing the degree of freedom of layout.

According to an embodiment of the present invention, the axis of theswinging center axis of the left arm is disposed on the right side ofthe longitudinally extending vehicle body center line, whereas theswinging center axis of the right arm is disposed on the left side ofthe longitudinally extending vehicle body center line. This enables thelength of the left and right arms to be enlarged effectively, ascompared with the case where the swinging center axis of the left arm isdisposed on the left side of the longitudinally extending vehicle bodycenter line whereas the swinging center axis of the right arm isdisposed on the right side of the longitudinally extending vehicle bodycenter line. In addition, it is possible to reduce the length of theleft and right arm members in the vehicle width direction (the wholewidth) and, therefore, to reduce the vehicle width, as compared with thecase where the swinging center axis of the left arm is disposed on theleft side of the longitudinally extending vehicle body center linewhereas the swinging center axis of the right arm is disposed on theright side of the longitudinally extending vehicle body center line.

According to an embodiment of the present invention, the swinging centeraxes of those ones one of the upper arms and the lower arms whichcorrespond to the greater one of the above-mentioned distances are outof alignment with each other, as viewed from the direction along theaxis of the support shaft. Owing to this configuration, clearance can besecured between those ones of the upper arms and lower arms which areliable to interfere with component parts surrounding the front wheels atthe time of swinging of the arm members and the surrounding componentparts. As a result, interference among vehicle component parts can beavoided effectively.

According to an embodiment of the present invention, the above-mentioneddistance for the lower arms is set smaller than the above-mentioneddistance for the upper arms. This ensures that a minimum road clearancecan be secured more easily as compared with the case where the distancefor the lower arms is set greater than the distance for the upper arms.With the swinging center axes of the left and right upper arms set outof alignment with each other as viewed from the direction along the axisof the support shaft, clearance can be secured between the upper arms(which are liable to interfere with the component parts surrounding thefront wheels at the time of swinging of the arm members) and thesurrounding component parts, so that interference among vehiclecomponent parts can be avoided effectively. Therefore, interferenceamong vehicle component parts can be obviated effectively while securinga minimum road clearance.

According to an embodiment of the present invention, the base portion ofthe left arm and the base portion of the right arm are supported by theeccentric collars fitted to the same support shaft. With thisconfiguration, it is possible to enlarge the length of the left andright arms by just a required amount without an increase in weight, ascompared with the case where the number of the support shafts isincreased by, for example, providing the support shafts on the basis ofeach of the left arm and the right arm.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is a left side view of a vehicle body front portion of atwo-front-wheeled saddle type vehicle in one embodiment of the presentinvention;

FIG. 2 is a right side view of a two-front-wheel suspension system ofthe saddle type vehicle in a state where a right front wheel has beenremoved;

FIG. 3 is a view along arrow III of FIG. 2 (a front view as viewed froman axial direction of upper and lower roll shafts);

FIG. 4 is a view along arrow IV of FIG. 2 (a top plan view as viewedfrom an axial direction of a steering shaft);

FIG. 5 is a view along arrow V of FIG. 2 (a bottom view as viewed fromthe axial direction of the steering shaft);

FIG. 6 is a perspective view of the two-front-wheel suspension system;

FIGS. 7(a), 7(b) and 7(c) illustrates a steering link mechanism of thetwo-front-wheel suspension system, wherein 7(a) depicts a state when aturning angle is 0 degrees, 7(b) depicts a state at the time of steeringto the left, and 7(c) depicts a state at the time of steering to theright;

FIG. 8 is a view along an arrow corresponding to FIG. 3, showing a statewhere a vehicle body rolls to the right side;

FIG. 9 is a right side view of a front suspension frame body;

FIG. 10 is a view including a sectional view taken along line X-X ofFIG. 2;

FIG. 11 is an exploded perspective view of left and right upper arms ofthe two-front-wheel suspension system;

FIG. 12 is an enlarged view of FIG. 3;

FIG. 13 is a view including a section along line XIII-XIII of FIG. 4 (arear view as viewed from the axial direction of the upper and lower rollshafts);

FIGS. 14(a), 14(b) and 14(c) shows rear views of the two-front-wheelsuspension system along the upper and lower roll shafts at the time ofsteering to the left, wherein 14(a) depicts a state when the vehiclebody is upright, 14(b) depicts a state when the vehicle body rolls tothe left (a state at the time of banking at a bank angle slightlyshallower than a full-bank state), and 14(c) depicts a state when thevehicle body rolls to the left (a substantially full-bank state);

FIGS. 15(a), 15(b) and 15(c) illustrates the steering link mechanism ofthe two-front-wheel suspension system at the time of steering to theleft, wherein 15(a) depicts a state when the vehicle body is upright,15(b) depicts a state when the vehicle body rolls to the left (a stateat the time of banking at a bank angle slightly shallower than afull-bank state), and 15(c) depicts a state when the vehicle body rollsto the left (a substantially full-bank state);

FIG. 16 is a top plan view corresponding to FIG. 4, showing atwo-front-wheel suspension system according to a modification of theembodiment as viewed from an axial direction of a steering shaft; and

FIG. 17 is a perspective view, corresponding to FIG. 6, of thetwo-front-wheel suspension system according to the modification.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described below,referring to the drawings. It is to be noted that the directions such asforward, rearward, leftward and rightward directions in the followingdescription are the same as those directions with reference to a vehicledescribed hereinbelow, unless otherwise specified. In addition, atappropriate locations in the drawings used in the following description,there are shown an arrow FR indicative of the front side of the vehicle,an arrow LH indicative of the left-hand side of the vehicle, and anarrow UP indicative of the upper side of the vehicle. In addition, lineCL in the drawings is a longitudinally extending vehicle body centerline.

FIG. 1 shows a vehicle body front portion of a saddle type vehicle 1 inthe present embodiment. The saddle type vehicle 1 is a two-front-wheeledthree-wheel rolling type vehicle which includes a pair of left and rightfront wheels (steered wheels) 2 in left-right symmetry at vehicle bodyfront portions, and a rear wheel (not shown) as a single driving wheelat a vehicle body rear portion, and which is capable of lateral swinging(rolling) of the vehicle body with the left and right front wheels 2 ina set state. Symbol COW in the drawing indicates a cowling which coversa vehicle body front portion of the saddle type vehicle 1.

In the following, unless otherwise specified, description will be madeof a configuration in a condition where the left and right front wheels2 are grounded on a horizontal road surface R, the vehicle body is in a1G condition in which a load corresponding to the vehicle weight isexerted on a two-front-wheel suspension system 4 (described later), thevehicle body is in an upright state with a roll angle of 0degrees, andthe left and right front wheels 2 are in a straight ahead state with asteering angle of 0 degrees. The configuration described below is inleft-right symmetry about the center in the transverse direction, unlessspecified otherwise. In the present embodiment, the left-hand componentof a configuration composed of a pair of left and right components maybe denoted by a symbol attended by “L,” and the right-hand component maybe denoted by a symbol attended by “R” for distinguishing thecomponents, and they may be denoted by only the symbol not attended by“L” or “R.”

Referring to FIGS. 2, 3 and 6 in combination, the saddle type vehicle 1has a configuration in which a front suspension frame body 5 supportingthe two-front-wheel suspension system 4 is fixed to a front portion of,for example, a horizontal opposed engine 3 mounted in a center of thevehicle body. On the front suspension frame body 5, a lower portion of asteering shaft 12 extending vertically in a center in the transversedirection (in a center in the vehicle width direction) is rotatablysupported. A bar-type steering handle, or steering handlebar, 11 ismounted to an upper end portion of the steering shaft 12.

The steering shaft 12 has its center axis (steering axis) C1 disposed ona longitudinally extending vehicle body center line CL. The steeringaxis C1 is inclined so that its upper-side portion is located on therear side with reference to the vertical direction in side view. To alower end portion of the steering shaft 12, a base end portion of abottom bracket 12 a is fixed. To a tip portion of the bottom bracket 12a, a rear end portion of a link rod 13 extending in the longitudinalvehicle direction is connected. To a front end portion of the link rod13, a steering link mechanism 17 is connected. To the steering linkmechanism 17, left and right knuckle members 26L and 26R are connectedthrough left and right tie rods 16L and 16R, respectively. On the leftand right knuckle members 26L and 26R, the left and right front wheels2L and 2R are rotatably supported, respectively. Rotation of thesteering handlebar 11 and steering of the left and right front wheels 2Land 2R are interlocked with each other through the steering shaft 12,the link rod 13, the steering link mechanism 17, the left and right tierods 16L and 16R and the left and right knuckle members 26L and 26R.

Referring to FIGS. 2, 3 and 6, the two-front-wheel suspension system 4enables the vehicle body 1A inclusive of the front suspension frame body5 and the engine 3 and the like to roll with the left and right frontwheels 2L and 2R kept grounded, and enables the left and right frontwheels 2L and 2R to similarly roll in accordance with the rolling of thevehicle body 1A. By contrast, the two-front-wheel suspension system 4enables the left and right front wheels 2L and 2R to alternately move upand down with reference to the vehicle body 1A.

The two-front-wheel suspension system 4 is in a double wishbone form inwhich the left and right front wheels 2L and 2R are independentlysuspended, and in which outer link members 25 are supported throughupper arms 21 and lower arms 23 on left and right sides of the frontsuspension frame body 5 extending forwardly of the steering shaft 12 inthe center of the vehicle width direction. On the left and right outerlink members 25L and 25R, the left and right knuckle members 26L and 26Rand the front wheels 2L and 2R are supported in a steerable manner,respectively.

Those inner end portions of the left and right upper arms 21L and 21Rwhich are located at the center in the vehicle width direction aresupported on an upper portion of the front suspension frame body 5 in avertically swingable manner through an upper roll shaft 22 extendingsubstantially in the longitudinal direction of the vehicle. Those innerend portions of the left and right lower arms 23L and 23R which arelocated at the center in the vehicle width direction are supported on alower portion of the front suspension frame body 5 in a verticallyswingable manner through a lower roll shaft 24 parallel to the upperroll shaft 22. Axes C2 and C3 of the upper and lower roll shafts 22 and24 are disposed in a forwardly upwardly inclined posture with a smallerinclination angle with reference to the horizontal direction as comparedwith a direction which is orthogonal to the axis C1 of the steeringshaft 12 in side view.

On outer end portions of the left and right upper arms 21L and 21R,upper end portions of the left and right outer link members 25L and 25Rare supported in a swingable manner through an upper outer swing shaft25 a parallel to the upper and lower roll shafts 22 and 24. On outer endportions of the left and right lower arms 23L and 23R, lower endportions of the left and right outer link members 25L and 25R aresupported in a swingable manner through a lower outer swing shaft 25 bparallel to the upper and lower roll shafts 22 and 24.

As viewed along the axial direction of the upper and lower roll shafts22 and 24, all the left and right upper arms 21L and 21R, the left andright lower arms 23L and 23R and the left and right outer link members25L and 25R are disposed in the forms of parallel links on the left andright sides of the vehicle body, respectively. This configurationensures that when the left and right upper arms 21L and 21R and the leftand right lower arms 23L and 23R swing vertically, the left and rightouter link members 25L and 25R, the left and right knuckle members 26Land 26R and the left and right front wheels 2L and 2R are moved up anddown in a substantially parallel manner (see FIG. 8).

In addition, as viewed along the axial direction of the upper and lowerroll shafts 22 and 24, the left and right tie rods 16L and 16R are alsoprovided to be substantially parallel to and equal in length to the leftand right upper arms 21L and 21R and the left and right lower arms 23Land 23R. These members are disposed in the forms of parallel links onthe left and right sides of the vehicle body, respectively. Thisconfiguration ensures that when the left and right upper arms 21L and21R and the left and right lower arms 23L and 23R swing up and down, theleft and right tie rods 16L and 16R also swing up and down substantiallyin parallel to the left and right upper arms 21L and 21R and the leftand right lower arms 23L and 23R, thereby suppressing the influence onthe steering angles of the left and right front wheels 2L and 2R.

Left and right shock absorber units 31L and 31R which bear loads on theleft and right front wheels 2L and 2R respectively extend substantiallyvertically, on the upper side of rear portions of the left and rightlower arms 23L and 23R. The left and right shock absorber units 31L and31R have their lower end portions connected respectively to the left andright lower arms 23L and 23R, and have their upper end portionsconnected respectively to left and right end portions of a shockabsorber support arm 44 which extends substantially in the transversedirection. The shock absorber support arm 44 has a configuration whereinits base portion 45 (shaft support portion) at the center in thetransverse direction is supported on the front suspension frame body 5in a swingable manner through a shock absorber swing shaft 45 a parallelto the upper and lower roll shafts 22 and 24.

Left and right arm portions 44 aL and 44 aR integrally possessed by theshock absorber support arm 44 are disposed in the forms of parallellinks on the left and right sides of the vehicle body together with theleft and right lower arms 23L and 23R and the left and right shockabsorber units 31L and 31R.

Referring to FIGS. 2, 6 and 9, the front suspension frame body 5 isfixed to a front portion of the engine 3 through a mount frame 5 a. Thefront suspension frame body 5 includes a frame main body 6 which isdisposed at the center in the vehicle width direction and which has agate-like shape opening upward in side view, and a pair of left andright reinforcement beams 6 a arranged between left and right outsideportions of the frame main body 5 and the mount frame 5 a. The frontsuspension frame body 5 is provided to be forwardly upwardly inclined asa whole. The frame main body 6 and the left and right reinforcementbeams 6 a are provided in an integral fashion by forming integrally froma metallic material or by joining a plurality of members by welding,fastening or the like. The inclination of the front suspension framebody 5 is such that the front suspension frame body 5 is substantiallyparallel to the roll shafts 22 and 24 of the upper arms 21 and the lowerarms 23.

The frame main body 6 is provided in a flat shape suppressed in atransverse dimension. The frame main body 6 includes a rear side portion7, a lower side portion 8 and a front side portion 9 which form thegate-like shape. The upper opening portion of the gate-like shape of theframe main body 6 is indicated by symbol 6 b.

The rear side portion 7 includes a mount connection portion 7 aconnected and fixed to a substantially vertical front surface portion ofthe mount frame 5 a; a shaft support portion 7 b for supporting a lowerportion of the steering shaft 12 for rotation about the steering axis C1and a lower arm rear support portion 7 c for supporting rear baseportions 23 bL and 23 bR of the left and right lower arms 23L and 23R ofthe two-front-wheel suspension system 4 for vertical swinging; a forwardextending portion 7 d extending to the front side of the shaft supportportion 7 b. A shock absorber arm support portion 7 e is provided on theupper side of the front extending portion 7 d with an actuator rear endsupport portion 7 f provided on the front side of the shock absorber armsupport portion 7 e.

The lower arm rear support portion 7 c has a gate-like shape openingdownward in side view for supporting the rear base portions 23 bL and 23bR of the left and right lower arms 23L and 23R on the lower sidethereof. The rear base portions 23 bL and 23 bR of the left and rightlower arms 23L and 23R are disposed to be aligned in a front-rearrelationship. The rear base portions 23 bL and 23 bR are supported bythe lower arm rear support portion 7 c through a lower roll shaft 24 bwhich is forwardly upwardly inclined. In a space on the upper side ofthe lower arm rear support portion 7 c, there are disposed a lower endportion of the steering shaft 12 which penetrates the shaft supportportion 7 b downward and the bottom bracket 12 a.

The forward extending portion 7 d extends substantially in parallel tothe upper and lower roll shafts 22 and 24. The shock absorber armsupport portion 7 e over the forward extending portion 7 d has agate-like shape opening to the upper side in a side view. The baseportion 45 at the center in the transverse direction of the shockabsorber support arm 44 extending in the transverse direction isdisposed on the upper side of the shock absorber arm support portion 7e. The base portion 45 of the shock absorber support arm 44 is supportedby the shock absorber arm support portion 7 e of the frame main body 6through the shock absorber swing shaft 45 a which is forwardly upwardlyinclined to be parallel to the upper and lower roll shafts 22 and 24.Front end portions of the left and right reinforcement beams 6 a areconnected and fixed to left and right outer sides of a front end portionof the forward extending portion 7 d by fastening or the like. Rear endportions of the left and right reinforcement beams 6 a are connected andfixed to left and right outer sides of the rear side portion 7 in thevicinity of the mount frame 5 a by fastening or the like.

To the actuator rear end support portion 7 f on the front side of theshock absorber arm support portion 7 e, a rear end portion 42 a of ahousing 42 of an actuator 41 is connected and fixed. The housing 42 ofthe actuator 41 has a hollow cylindrical shape parallel to and coaxialwith the shock absorber swing shaft 45 a. The housing 42 is provided inan integral form by, for example, integrally forming from a metallicmaterial or joining a plurality of members by welding, fastening or thelike. At the outer circumference of the rear end portion 42 a of thehousing 42, a plurality of rear end mount portions 42 b are integrallyprovided. At the outer circumference of the actuator rear end supportportion 7 f of the frame main body 6, a plurality of frame-side mountportions 7 g corresponding to the rear end mount portions 42 b of thehousing 42 are integrally provided. To each of the frame-side mountportions 7 g, the corresponding rear end mount portion 42 b is connectedand fixed by fastening or the like.

The lower side portion 8 of the frame main body 6 extend obliquelyforwardly upwardly in parallel to the upper and lower roll shafts 22 and24. On the lower side of a front end portion of the lower side portion8, there is provided a lower arm front support portion 8 a wherein frontbase portions 23 aL and 23 aR of the left and right lower arms 23L and23R are supported so that they can swing up and down. The lower armfront support portion 8 a has a gate-like shape opening to the lowerside in side view, and supports the front base portions 23 aL and 23 aRof the left and right lower arms 23L and 23R in the inside thereof.

The front base portions 23 aL and 23 aR of the left and right lower arms23L and 23R are disposed to be aligned in a front-rear relationship. Thefront base portions 23 aL and 23 aR are supported by the lower arm frontsupport portion 8 a through a lower roll shaft 24 a which is inclinedforwardly upward. The lower roll shaft 24 a is coaxial with the lowerroll shaft 24 b of the lower arm rear support portion 7 c, and they areconfigured as the integral lower roll shaft 24 from, for example, anelongate shaft penetrating a lower portion of the frame main body 6 inthe longitudinal vehicle direction. It is to be noted that the lowerroll shafts 24 a and 24 b may be formed as separate bodies from eachother.

The front side portion 9 of the frame main body 6 includes an upper armfront support portion 9 a which is provided at the front side of anupper end portion of the front side portion 9 and which supports frontbase portions 21 aL and 21 aR of the left and right upper arms 21L and21R in a vertically swingable manner with a rearward extending portion 9b extending to the rear side of the upper arm front support portion 9 a.A link support portion 9 c is provided at a lower portion of therearward extending portion 9 b with an actuator front lower supportportion 9 d which is provided at an upper portion of the rearwardextending portion 9 b and which supports the lower side of a frontportion of the housing 42 of the actuator 41.

At the lower side of the front portion of the housing 42, a front lowermount portion 42 c is integrally provided. The front lower mount portion42 c is connected and fixed to the actuator front lower support portion9 d of the frame main body 6 by fastening or the like. The upper openingportion 6 b of the frame main body 6 having the gate-like shape in sideview is closed up by the housing 42 of the actuator 41, whereby thefront suspension frame body 5 having a closed loop structure which isclosed in side view is configured. More specifically, the housing 42 ofthe actuator 41 functions also as part of the front suspension framebody 5 of the vehicle body 1A.

A rear end portion of the rearward extending portion 9 b, together witha front end portion of the forward extending portion 7 d of the rearside portion 7, constitutes an upper arm rear support portion 9 e whichsupports rear base portions 21 bL and 21 bR of the left and right upperarms 21L and 21R in a vertically swingable manner.

The rear base portions 21 bL and 21 bR of the left and right upper arms21L and 21R are disposed to be aligned in a front-rear relationship. Therear base portions 21 bL and 21 bR are supported by the upper arm rearsupport portion 9 e through an upper roll shaft 22 b which is inclinedforwardly upward. The front base portions 21 aL and 21 aR of the leftand right upper arms 21L and 21R are disposed to be aligned in afront-rear relationship. The front base portions 21 aL and 21 aR aresupported by the upper arm front support portion 9 a through an upperroll shaft 22 a which is inclined forwardly upward. The upper rollshafts 22 a and 22 b are coaxial with each other, and are configured asthe integral upper roll shaft 22 from, for example, an elongate shaftwhich penetrates an upper portion of the frame main body 6 in thefront-rear direction. It is to be noted that the upper roll shafts 22 aand 22 b may be formed as separate bodies from each other.

Onto the upper roll shaft 22 having the center axis C2 disposed on thelongitudinally extending vehicle body center line CL, the front baseportions 21 aL and 21 aR and the rear base portions 21 bL and 21 bR ofthe left and right upper arms 21L and 21R are individually supportedthrough eccentric collars (not shown). The left and right upper arms 21Land 21R swing about bearings externally fitted to the eccentric collars,whereby the swinging centers of the left and right upper arms 21L and21R can be a little offset in the vehicle width direction from the axialcenter of the upper roll shaft 22. More specifically, the swingingcenter of the left upper arm 21L is offset to the right side of the axisC2 of the upper roll shaft 22, whereas the swinging center of the rightupper arm 21R is offset to the left side of the axis C2 of the upperroll shaft 22. It is to be noted that the swinging center axis C3 of theleft and right lower arms 23L and 23R (corresponding to the center axisC3 of the lower roll shaft 24) is disposed on the longitudinallyextending vehicle body center line CL.

Referring to FIGS. 2, 4 and 6, the actuator 41 is an electric motor orfluidic apparatus which generates a torque about a center axis C7 of thehousing 42. The actuator 41 has, at a rear portion thereof, a frontswing arm 43 which protrudes obliquely to a left upper rear side andwhich swings about the axis C7. A driving shaft (output portion) 41 a isprovided sharing the axis C7 in the actuator 41. The front swing arm 43is fixed to the driving shaft 41 a and swings about the axis C7. Thefront swing arm 43 and a rear swing arm 46 of the shock absorber supportarm 44 are spaced from each other along the axial direction of theactuator 41. At a connection portion 40 between the front swing arm 43and the rear swing arm 46, there is provided a connection device 47(load detection unit) which enables the front and rear swing arms 43 and46 to swing as one body. The connection device 47 functions also as aload detection unit which detects a load transmitted between the frontand rear swing arms 43 and 46.

The connection device 47 has a hollow cylindrical shape. A center axisC10 of the connection device 47 is disposed to be orthogonal to theshock absorber swing shaft 45 a and be along the vehicle widthdirection. The connection device 47 incorporates a load sensor forelectrical detection of a load (torque) about the shock absorber swingshaft 45 a which is generated between the front and rear swing arms 43and 46. A detected value obtained by the detection is inputted to an ECU(Electronic Control Unit) 49 as a control unit for controlling theoperation of the actuator 41. The ECU 49 controls the actuator 41, onthe basis of the results of the detection by the connection device 47functioning as the load detection unit.

The connection device 47 is connected so as to be rotatable relative tothe front and rear swing arms 43 and 46. More specifically, theconnection portion 40 is provided with a connection link 48 forconnection between left and right outer end portions of the connectiondevice 47 and tip portions 43 b and 46 b of the front and rear swingarms 43 and 46. The connection link 48, which extends along the vehiclewidth direction, is provided at left and right end portions thereof withleft and right spherical bearings 48 a and 48 b as connection portionsfor connection with the tip portions 43 b and 46 b of the front and rearswing arms 43 and 46, respectively. Through the left spherical bearing48 a, the left end portion of the connection link 48 is connected to thetip portion 43 b of the front swing arm 43 by a bolt 47 a inserted fromthe rear side. More specifically, through the right spherical bearing 48b, the right end portion of the connection link 48 is connected to thetip portion 46 b of the rear swing arm 46 by a bolt 47 b inserted fromthe front side.

The front swing arm 43 extends by protruding obliquely toward a leftupper rear side from a base portion 43 a exposed to a shaft supportportion of the driving shaft 41 a, to reach the tip portion 43 b whichis connected to the left end portion of the connection link 48 throughthe left spherical bearing 48 a. The rear swing arm 46 extends byprotruding obliquely toward a right upper front side from a base portion46 a exposed to the shaft support portion 45 of the shock absorber swingshaft 45 a, to reach the tip portion 46 b which is connected to theright end portion of the connection link 48 through the right sphericalbearing 48 b.

As viewed from an axis C8 about which the shock absorber support arm 44can swing, the base portion 43 a of the front swing arm 43 is opposed tothe base portion 46 a of the rear swing arm 46, with a spacingtherebetween in the direction along the axis C8.

Referring to FIG. 3, as the actuator 41 operates, the front swing arm 43describes a circular arc-shaped trajectory KC centered on the swingingcenter (axis C7) of the front swing arm 43 of the actuator 41. As viewedfrom the axis C8, the tip portion 43 b of the front swing arm 43 (theconnection portion between the connection device 47 and the front swingarm 43) is positionally deviated from the tip portion 46 b of the rearswing arm 46 (the connection portion between the connection device 47and the rear swing arm 46) in a direction along the trajectory KC. Morespecifically, as viewed from the axis C8, the tip portion 43 b of thefront swing arm 43 is deviated to the left side from the longitudinallyextending vehicle body center line CL, in the direction along thetrajectory KC. The tip portion 46 b of the rear swing arm 46 is deviatedto the right side from the longitudinally extending vehicle body centerline CL, in the direction along the trajectory KC.

The load about the shock absorber swing shaft 45 a which is generatedbetween the front and rear swing arms 43 and 46 is generated accordingto an operation resistance (torque) of the front swing arm 43 when theshock absorber support arm 44 is going to swing in relation to theactuator 41 supported on the vehicle body side. More specifically, whenthe vehicle body swings to the left and right (rolls), a load about theshock absorber swing shaft 45 a is generated between the front and rearswing arms 43 and 46 in accordance with the operation resistance of thefront swing arm 43. The ECU 49 controls the driving of the actuator 41according to a detected value of the load. The ECU 49 can control theactuator 41 so as to reduce at least the load inputted from the rearswing arm 46 to the front swing arm 43, namely, the load inputted fromthe shock absorber support arm 44 to the actuator 41, of the loadtransmitted between the front and rear swing arms 43 and 46.

For example, from a detected value supplied from an inclination sensor(acceleration sensor) provided on the vehicle body, the ECU 49 detects amoment in a falling direction and a rising direction which acts on thevehicle body, and controls the driving of the actuator 41 so that themoment will not become excessively great.

It is to be noted that the ECU 49 may be so configured that, forexample, when the saddle type vehicle 1 is in a stopped state or a lowvehicle speed state, the ECU 49 controls the driving of the actuator 41so as to maximize the resistance to rolling of the vehicle body, andwhen the saddle type vehicle 1 is in a middle or high vehicle speedstate, the ECU 49 controls the driving of the actuator 41 so as toweaken the resistance to rolling of the vehicle body.

Referring to FIGS. 4 and 6, the upper arm 21 integrally includes thefront and rear base portions 21 a and 21 b which are rotatably supportedon upper portions of the frame main body 6; a link upper support portion21 c which rotatably supports an upper end portion of the outer linkmember 25 at a transversely outer end portion of the upper arm 21; afront arm body 21 d arranged between the front base portion 21 a and thelink upper support portion 21 c; and a rear arm body 21 e arrangedbetween the rear base portion 21 b and a link upper member.

The front and rear base portions 21 a and 21 b are each formed in ahollow cylindrical shape parallel to the upper roll shaft 22. The upperroll shaft 22 is disposed to extend through the inside of the front andrear base portions 21 a and 21 b. In the present embodiment, the frontand rear base portions 21 aL and 21 bL of the left upper arm 21L arealigned with the front and rear base portions 21 aR and 21 bR of theright upper arm 21R, so as to overlap with the latter from the rearside, and these base portions are supported by the frame main body 6through the upper roll shaft 22. In other words, as viewed in the axialdirection of the upper roll shaft 22 (as viewed from the direction alongthe axis C2), the front and rear base portions 21 aL and 21 bL of theleft upper arm 21L and the front and rear base portions 21 aR and 21 bRof the right upper arm 21R overlap with each other.

The left and right upper arms 21L and 21R are so configured so that thefront and rear base portions 21 a and 21 b on the left side differ fromthose on the right side in front-rear-directional position, but that thelink upper support portions 21 c on the left and right sides are thesame in front-rear-directional position. For this reason, the left andright upper arms 21L and 21R are formed in left-right asymmetry bymaking the front and rear arm bodies 21 d and 21 e different in a bentshape or the like.

Referring to FIGS. 5 and 6, the lower arm 23 integrally includes thefront and rear base portions 23 a and 23 b which are rotatably supportedon lower portions of the frame main body 6; a link lower support portion23 c which rotatably supports a lower end portion of the outer linkmember 25 at a transversely outer end portion on the arm's front side; afront arm body 23 d arranged between the front base portion 23 a and thelink lower support portion 23 c; and a rear arm body 23 e arrangedbetween the rear base portion 23 b and a link lower member. The rear armbody 23 e includes a short arm 23 e 1 extending outwardly in the vehiclewidth direction from the rear base portion 23 b; a longitudinal beam 23e 2 arranged between a front end portion of the short arm 23 e 1 and anintermediate portion of the front arm body 23 d; and an inclined beam 23e 3 arranged between an intermediate portion of the longitudinal beam 23e 2 and the link lower support portion 23 c. On the outer side of theshort arm 23 e 1 in the vehicle width direction, a shock absorber lowersupport arm 23 e 4 is provided in the manner of extending the short arm23 e 1. More specifically, a rear end portion of the longitudinal beam23 e 2 is connected to an intermediate portion of an arm body composedof the short arm 23 e 1 and the shock absorber lower support arm 23 e 4.A tip portion of the shock absorber lower support arm 23 e 4 is a shockabsorber lower support portion 23 e 5. The longitudinal beams 23 e 2form a closed loop together with the frame main body 6 (see FIG. 5),whereby the rigidity of the lower arm 23 in the transverse direction ofthe vehicle can be enhanced.

The front and rear base portions 23 a and 23 b are each formed in ahollow cylindrical shape parallel to and coaxial with the lower rollshaft 24. The lower roll shaft 24 is disposed to extend through theinside of the front and rear base portions 23 a and 23 b. In the presentembodiment, the front and rear base portions 23 aL and 23 bL of the leftlower arm 23L are aligned with the front and rear base portions 23 aRand 23 bR of the right lower arm 23R, so as to overlap with the latterfrom the rear side, and these base portions are supported by the framemain body 6 through the lower roll shaft 24. More specifically, asviewed in the axial direction of the lower roll shaft 24 (as viewed fromthe direction along the axis C3), the front and rear base portions 23 aLand 23 bL of the left lower arm 23L and the front and rear base portions23 aR and 23 bR of the right lower arm 23R overlap with each other.

The left and right lower arms 23L and 23R are so configured that thefront and rear base portions 23 a and 23 b on the left side differ fromthose on the right side in longitudinal-directional position, but thatthe link lower support portions 23 c and the shock absorber lowersupport portions 23 e 5 on the left and right sides are the same inlongitudinal-directional position. For this reason, the left and rightlower arms 23L and 23R are formed in left-right asymmetry by making thefront and rear arm bodies 23 d and 23 e different in a bent shape or thelike.

Referring to FIG. 3, the distance from an axle center C5 of the frontwheels 2L and 2R to transversely outer end portions 21 cL and 21 cR ofthe left and right upper arms 21L and 21R (the link upper supportportions 21 c which rotatably support the upper end portions of theouter link members 25) is denoted by symbol L1. The distance from theaxle center C5 to transversely outer end portions 23 cL and 23 cR of theleft and right lower arms 23L and 23R (the link lower support portions23 c which rotatably support the lower end portions of the outer linkmembers 25) is denoted by symbol L2. The distance L1 means the distancefrom the axle center C5 to the centers of the upper outer swing shafts25 a at the transversely outer end portions 21 cL and 21 cR of the leftand right upper arms 21L and 21R, as viewed in the axial direction ofthe upper and lower roll shafts 22 and 24 (as viewed in a directionalong the axes C2 and C3). The distance L2 means the distance from theaxle center C5 to the centers of the lower outer swing shafts 25 b atthe transversely outer end portions 23 cL and 23 cR of the left andright lower arms 23L and 23R, as viewed in the axial direction of theupper and lower roll shafts 22 and 24.

In the present embodiment, the distance L2 is smaller than the distanceL1 (L2<L1). It is to be noted that the distance L2 may be greater thanthe distance L1. In other words, it is sufficient for the distance L1and the distance L2 to be different from each other.

Referring to FIGS. 10 to 12, in the present embodiment, as viewed in theaxial direction of the upper and lower roll shafts 22 and 24, a centeraxis C11 of the front and rear base portions 21 aL and 21 bL of the leftupper arm 21L (the swinging center axis of the left upper arm 21L) and acenter axis C12 of the front and rear base portions 21 aR and 21 bR ofthe right upper arm 21R (the swinging center axis of the right upper arm21R) are out of alignment with each other. More specifically, as viewedin the axial direction of the upper and lower roll shafts 22 and 24, thecenter axis C11 of the front and rear base portions 21 aL and 21 bL ofthe left upper arm 21L is disposed on the right side of thelongitudinally extending vehicle body center line CL, whereas the centeraxis C12 of the front and rear base portions 21 aR and 21 bR of theright upper arm 21R is disposed on the left side of the longitudinallyextending vehicle body center line CL.

It is to be noted that in the case where the distance L2 is greater thanthe distance L1, a center axis of the front and rear base portions 23 aLand 23 bL of the left lower arm 23L and a center axis of the front andrear base portions 23 aR and 23 bR of the right lower arm 23R may be outof alignment with each other, as viewed in the axial direction of theupper and lower roll shafts 22 and 24. More specifically, of the leftand right upper arms 21L and 21R and the left and right lower arms 23Land 23R, those corresponding to the greater one of the distances L1 andL2 may have their swinging center axes out of alignment with each other,as viewed in the axial direction of the upper and lower roll shafts 22and 24.

The front and rear base portions 21 aL and 21 bL of the left upper arm21L and the front and rear base portions 21 aR and 21 bR of the rightupper arm 21R are supported by eccentric collars 50 fitted to the sameupper roll shaft 22.

A support structure for the front base portion 21 aL of the left upperarm 21L and the front base portion 21 aR of the right upper arm 21R, ofthe front and rear base portions 21 aL and 21 bL of the left upper arm21L and the front and rear base portions 21 aR and 21 bR of the rightupper arm 21R, will be described below referring to FIGS. 10 to 12. Itis to be noted that a support structure for the rear base portion 21 bLof the left upper arm 21L and the rear base portion 21 bR of the rightupper arm 21R is the same as the support structure for the front baseportion 21 aL of the left upper arm 21L and the front base portion 21 aRof the right upper arm 21R. Therefore, a detailed description thereof isomitted.

The front base portions 21 aL and 21 aR of the left and right upper arms21L and 21R extend in parallel to the axis C2 of the upper roll shaft22, and have hollow cylindrical shapes centered on the center axes C11and C12, respectively. Outer circumference portions of the front baseportions 21 aL and 21 aR of the left and right upper arms 21L and 21Rare integrally connected to transversely inner ends of the left andright front arm bodies 21 d which extend along the vehicle widthdirection. The left and right front arm bodies 21 d are hollow.

Referring to FIG. 10, a length S1 of the front base portions 21 aL and21 aR of the left and right upper arms 21L and 21R extends along theaxis C2 and a length S2 (outside diameter) of the left and right frontarm bodies 21 d extends along the axis C2. In the left and right upperarms 21L and 21R, the length S1 values of the left and right front baseportions 21 aL and 21 aR are approximately equal, and the length S2values of the left and right front arm bodies 21 d are alsoapproximately equal. In the present embodiment, the length S1 of thefront base portions 21 aL and 21 aR is greater than the length S2 of thefront arm bodies 21 d (S1>S2). By this configuration, support rigidityof the left and right upper arms 21L and 21R with respect to the upperroll shaft 22 a can be enhanced, as compared with the case where thelength S1 of the front base portions 21 aL and 21 aR is equal to orsmaller than the length S2 of the front arm bodies 21 d.

The front base portions 21 aL and 21 aR of the left and right upper arms21L and 21R are formed with circular insertion holes 21 h which areopening in a direction along the axis C2 and which are centered on thecenter axes C11 and C12, respectively.

Front and rear plates 51 are disposed at the front of the front baseportion 21 aR of the right upper arm 21R and at the rear of the frontbase portion 21 aL of the left upper arm 21L. An intermediate plate 52is disposed between a rear portion of the front base portion 21 aR ofthe right upper arm 21R and a front portion of the front base portion 21aL of the left upper arm 21L. Each of the plates 51 and 52 is formed ina plate-like form which has a rectangular shape elongated in a directionorthogonal to the axis C2 (in a vertical direction as viewed in theaxial direction of the upper roll shaft 22 as depicted in FIG. 12) andwhich has a thickness in the direction along the axis C2.

The plates 51 and 52 are formed therein with circular insertion holes 51h and 52 h which are opening in the direction along the axis C2 andwhich are centered on the axis C2. The insertion hole 51 h in the frontplate 51 is formed in a vertically intermediate portion of a plate mainbody on the left side with respect to the center in the transversedirection. The insertion hole 52 h in the intermediate plate 52 isformed in a vertically intermediate portion of a plate main body in thecenter in the transverse direction. The insertion hole 51 h in the rearplate 51 is formed in a vertically intermediate portion of a plate mainbody on the right side with respect to the center in the transversedirection.

The front and rear plates 51 are formed respectively with upper andlower insertion holes 51 i for fixation to the upper arm front supportportion 9 a. The upper and lower insertion holes 51 i are verticallyspaced by a predetermined distance from the insertion hole 51 h forinsertion of the upper roll shaft 22 a, are opening in the directionparallel to the axis C2, and have a circular shape smaller than that ofthe insertion hole 51 h.

The front and rear plates 51 are fixed to the upper arm front supportportion 9 a by a bolt or the like extending through the insertion hole51 i from the rear side or front side along the axis C2. A bolt mountingportion of each of the front and rear plates 51 is formed with spotfacing (not shown). For example, the depth of the spot facing (themaximum depth in the normal direction to a major surface of each of thefront and rear plates 51) is so sized that when fixing the front andrear plates 51 to the upper arm front support portion 9 a by a bolt orthe like, the bolt head does not protrude from the major surface of eachof the front and rear plates 51.

The support structure for the front base portion 21 aL of the left upperarm 21L and the front base portion 21 aR of the right upper arm 21R isas follows. In a state in which the front base portions 21 aL and 21 aRof the left and right upper arms 21L and 21R are disposed to be alignedin a front-rear relationship between a front portion and a rear portionof the upper arm front support portion 9 a, the upper roll shaft 22 a(bolt) is engaged with and fastened to a nut (not shown) through aninsertion hole 9 h in the upper arm front support portion 9 a and theinner circumferences of the front base portions 21 aL and 21 aR of theleft and right upper arms 21L and 21R.

On the outer circumference of the upper roll shaft 22 a, there areprovided, for example the eccentric collars 50 which support ballbearings 53 and in which the upper roll shaft 22 a is inserted; andannular seal members 54 for ensuring sealing properties between theinner circumferences of the front base portions 21 aL and 21 aR of theleft and right upper arms 21L and 21R and the outer circumferences ofthe eccentric collars 50. In the present embodiment, the ball bearings53, the eccentric collars 50 and the seal members 54 are provided intwos aligned in a front-rear relationship along the axis C,respectively, in the front base portions 21 aL and 21 aR of the left andright upper arms 21L and 21R.

The front base portions 21 aL and 21 aR of the left and right upper arms21L and 21R are swingably supported on the upper arm front supportportion 9 a through the upper roll shaft 22 a, the plates 51 and 52, theeccentric collars 50, and the ball bearings 53. The upper roll shaft 22a, the plates 51 and 52, the eccentric collars 50, and inner races ofthe ball bearings 53 are stationarily supported on the upper arm frontsupport portion 9 a. The front base portions 21 aL and 21 aR of the leftand right upper arms 21L and 21R are supported on the outercircumferences of the eccentric collars 50 so that they are swingableabout the bearings.

At each of the inner circumferences of the front base portions 21 aL and21 aR of the left and right upper arms 21L and 21R, an annularprojection 21 g projecting radially inwardly is integrally formed. Outerraces of the ball bearings 53 abut on the projection 21 g from the frontand rear sides of the projection 21 g along the axis C2, at the innercircumferences of the front base portions 21 aL and 21 aR of the leftand right upper arms 21L and 21R. The eccentric collars 50 have theirend faces (orthogonal to the axis C2) abutting on each other from thefront and rear sides along the axis C2 at a position exposed to theprojection 21 g.

Each of the eccentric collars 50 integrally includes a hollowcylindrical cylinder portion 50 a which extends in parallel to the axisC2 and has a center axis coinciding with the center axis C11 or C12; ahead portion 50 b which has a hollow cylindrical shape greater than thecylinder portion 50 a in diameter and which has a bearing surface 50 s 1making contact with the plates 51 and 52; and a projecting portion 50 cwhich projects from a transversely one end side of the head portion 50 bto a side opposite to the cylinder portion 50 a and which has asemicircular bearing surface 50 s 2. For example, the eccentric collar50 is made of metal, and the components of the eccentric collar 50 areintegrally formed from the same material.

As viewed from the direction along the axis C2, the eccentric collar 50provided at the front base portion 21 aL of the left upper arm 21L hasan outer circumferential surface eccentrically deviated to the rightside from the axis C2. As viewed from the direction along the axis C2,the projecting portion 50 c of the eccentric collar 50 provided at thefront base portion 21 aL of the left upper arm 21L projects to a sideopposite to the cylinder portion 50 a, on the right side of the axis C2.

On the other hand, as viewed from the direction along the axis C2, theeccentric collar 50 provided at the front base portion 21 aR of theright upper arm 21R has an outer circumferential surface eccentricallydeviated to the left side from the axis C2. As viewed from the directionalong the axis C2, the projecting portion 50 c of the eccentric collar50 provided at the front base portion 21 aR of the right upper arm 21Rprojects to a side opposite to the cylinder portion 50 a, on the leftside of the axis C2.

Referring to FIG. 10, a left side surface 511 of the front plate 51makes contact with that surface 50 s 3 of the projecting portion 50 c ofthe front eccentric collar 50 provided at the front base portion 21 aRof the right upper arm 21R which is exposed to the axis C2. A left sidesurface 521 of the intermediate plate 52 makes contact with the surface50 s 3 of the projecting portion 50 c of the rear eccentric collar 50provided at the front base portion 21 aR of the right upper arm 21Rwhich is exposed to the axis C2. A right side surface 52 r of theintermediate plate 52 makes contact with that surface 50 s 3 of theprojecting portion 50 c of the front eccentric collar 50 provided at thefront base portion 21 aL of the left upper arm 21L which is exposed tothe axis C2.

A right side surface 51 r of the rear plate 51 makes contact with thatsurface 50 s 3 of the projecting portion 50 c of the rear eccentriccollar 50 provided at the front base portion 21 aL of the left upper arm21L which is exposed to the axis C2.

For example, when the plates 51 and 52 are fixed to the vehicle body 1Asuch as the upper arm front support portion 9 a, rotation of theprojecting portion 50 c of each eccentric collar 50 about the axis C2 isrestricted, so that each eccentric collar 50 can be restrained fromslipping off about the axis C2.

The eccentric collar 50 is formed with a circular insertion hole 50 hwhich is opening in the direction along the axis C2 and which iscentered on the axis C2. As viewed from the direction along the axis C2,the center axes C11 and C12 of the eccentric collars 50 provided at thefront base portions 21 aL and 21 aR of the left and right upper arms 21Land 21R are shifted from each other, with the axis C2 therebetween. Morespecifically, as viewed from the direction along the axis C2, the centeraxis C11 of the eccentric collar 50 provided at the front base portion21 aL of the left upper arm 21L is deviated to the right side of theaxis C2. On the other hand, the center axis C12 of the eccentric collar50 provided at the front base portion 21 aR of the right upper arm 21Ris deviated to the left side of the axis C2.

Referring to FIGS. 10 and 12, the deviation amount (the distance in thevehicle width direction) between the center axis C11 of the eccentriccollar 50 provided at the front base portion 21 aL of the left upper arm21L and the axis C2 of the upper roll shaft 22 a is denoted by symbolW1. In addition, the deviation amount (the distance in the vehicle widthdirection) between the center axis C12 of the eccentric collar 50provided at the front base portion 21 aR of the right upper arm 21R andthe axis C2 of the upper roll shaft 22 a is denoted by symbol W2. In thepresent embodiment, the deviation amount W1 between the center axis C11and the axis C2 and the deviation amount W2 between the center axis C12and the axis C2 is approximately equal, and are, for example, about 2mm.

Referring to FIGS. 2, 3 and 6, the outer link member 25 extendssubstantially vertically. On the outer side of a lower portion of theouter link member 25, there is provided a knuckle support portion 25 chaving a gate-like shape opening to a transversely outer side in frontview shown in FIG. 3. On the knuckle support portion 25 c, a baseportion 26 a of the knuckle member 26 is steerably supported, through asteering shaft (kingpin shaft) 27 which is substantially parallel to thesteering shaft 12 in side view. On the knuckle member 26, a front fender2 e is supported through front and rear stays 2 f.

The knuckle member 26 integrally includes the base portion 26 asupported by the outer link member 25; an axle support portion 26 bprovided at a vertically intermediate portion of the base portion 26 a;an outer rod connection portion 26 c provided forwardly of the axlesupport portion 26 b; and caliper support portions 26 d extendingforward from upper and lower portions of the base portion 26 a. On theaxle support portion 26 b, a hub 2 b of the front wheel 2 is rotatablysupported through an axle 28. A wheel 2 a of the front wheel 2 isfastened and fixed to the outside of the hub 2 b through a plurality offastening portions 29 (see FIG. 1). At the outer circumference of thehub 2 b, a brake rotor 2 d is supported to be rotatable integrally withthe hub 2 b. The brake rotor 2 d constitutes a front brake, on the basisof each of the left and right front wheels 2, together with a caliper 2c supported on the caliper support portion 26 d .

In the front view shown in FIG. 3, center axes (kingpin axes) C9L andC9R of left and right kingpin shafts 27L and 27R are disposed asvertical lines which are offset equidistantly to the left and the rightfrom the longitudinally extending vehicle body center line CL. In sideview, on the other hand, the kingpin axes C9 are each disposed at anupwardly rearward inclination. It is to be noted that the kingpin axesC9 may be inclined in the front view in correspondence with the offsetof the swinging center of the upper arms 21.

An intersection T1′ of a downward extension line of the kingpin axis C9with the road surface R in a side view is located forwardly of agrounding point T1 vertically under the axle center C5 of the frontwheel 2, thereby generating a caster offset. The inclination angle ofthe kingpin axis C9 against the vertical direction in side view is thecaster angle. The axle 28 of the front wheel 2 is offset to the frontside of the kingpin axis C9 in side view.

Each of tires of the left and right front wheels 2L and 2R has a treadsurface which is circular arc-shaped in section. At the time of banking(rolling) of the vehicle body, the left and right front wheels 2L and 2Rare inclined similarly to the vehicle body due to the action of thetwo-front-wheel suspension system 4, whereby the grounding points aredisplaced sideways from the centers of the tread surfaces.

In this instance, since the length of the left and right tie rods 16Land 16R, the length of the left and right upper arms 21L and 21R, andthe length of the left and right lower arms 23L and 23R are respectivelyequal, not any steering angle is generated even when the vehicle body isinclined.

Regulating means 60 (see FIG. 13) for regulating the turning angles ofthe front wheels 2L and 2R are provided between the link lower supportportions 23 c (which are transversely outer end portions of the left andright lower arms 23L and 23R) and the left and right knuckle members 26Land 26R. The left and right outer link members 25L and 25R are supportedon the left and right link upper and lower support portions 21 c and 23c so as to be swingable about the swing shafts 25 a and 25 b (swing axesC11 and C12). The left and right outer link members 25L and 25R supportthe knuckle members 26L and 26R in a steerable manner about the left andright kingpin shafts 27L and 27R (kingpin axes C9L and C9R) whichintersect the left and right swing shafts 25 a and 25 b (swing axes C11and C12), respectively.

In FIGS. 13 to 15 in the following, for convenience of explanation, theregulating means 60 between the link lower support portion 23 c of theleft lower arm 23L and the left knuckle member 26L will be described. Itis to be noted that the regulating means 60 between the link lowersupport portion 23 c of the right lower arm 23R and the right knucklemember 26R is equivalent to the regulating means 60 between the linklower support portion 23 c of the left lower arm 23L and the leftknuckle member 26L. Therefore, a detailed description thereof isomitted.

Referring to FIG. 13, the regulating means 60 includes a firstregulation member 61 provided at an outer end portion of the link lowersupport portion 23 c of the left outer link member 25L; and a secondregulation member 62 provided at a roller support portion 26 e on a rearlower side of the left knuckle member 26L. The first regulation member61 is disposed so as to overlap with an insertion portion 25 e forinsertion of the swing shaft 25 b of the left link lower support portion23 cL, as viewed from the direction along the swing shafts 25 a and 25 b(the swing axis C12L).

As the first regulation member 61, there is used a cam which regulatesthe turning angle of the front wheel 2L in conjunction with a variationin the swinging angle about the swing axis C12L. The second regulationmember 62 includes the cam 61 overlapping with the insertion portion 25e, as viewed in the direction along the swing axis C12L and a hollowcylindrical roller 62 a capable of rolling along the outer circumference61 a of the cam 61 (a cam protuberance located at a transversely outerend edge of the cam 61). The cam 61, by making contact with the roller62 a, rotates the roller 62 a about an axis C13. It is to be noted thatthe axis C13 is gradually inclined so that a vehicle rear portionthereof is located on a left upper side, as viewed in the directionalong the swing axis C12L, in an upright state of the vehicle body inwhich the left-right swinging angle is 0 degrees. In addition, in theupright state, the roller 62 a is spaced apart to the transversely outerside from the outer circumference 61 a of the cam 61.

The cam 61 is so formed as to reduce the turning angle of the frontwheel 2L when the swinging angle about the swing axis C12L exceeds apredetermined angle. The outer circumference 61 a of the cam 61 isformed in an S shape, as viewed in the direction along the swing axisC12L. More specifically, the outer circumference 61 a of the cam 61 hasan upper edge portion 63 having a circular arc shape centered on theswing axis C12L as viewed in the direction along the swing axis C12L; alower edge portion 64 protruding to a left lower side while graduallycurving from a lower end of the upper edge portion 63 toward a radiallyouter side of a circle centered on the swing axis C12L; and anintermediate edge portion 65 located in a vertically intermediate area(boundary area) between the upper edge portion 63 and the lower edgeportion 64.

Referring to FIGS. 2, 3 and 6, the shock absorber unit 31 includes arod-type damper 32 extending substantially vertically, and a coil spring33 wound around the damper 32. The shock absorber unit 31 is so inclinedthat its upper portion is located on the rear side with respect to thevertical direction in side view, and is disposed so as to extendorthogonally to the upper and lower roll shafts 22 and 24 in side view.In addition, the shock absorber unit 33 is disposed substantiallyvertically in front view shown in FIG. 3. It is to be noted that theshock absorber unit 31 may be inclined in front view correspondingly tothe offset of the swinging center of the upper arms 21.

Referring to FIGS. 4 and 5, as viewed in the axial direction of thesteering shaft 12, the turning trajectories KL and KR of the left andright front wheels 2L and 2R are in the shape of circular arcs centeredon the center axes (kingpin axes) C9L and C9R of the left and rightkingpin shafts 27L and 27R. As viewed in the axial direction of thesteering shaft 12, the left and right shock absorber units 31L and 31Rare disposed on the outer circumference sides of the turningtrajectories KL and KR of the left and right front wheels 2L and 2R,namely, on the radially outer sides of the circles centered on thekingpin axes C9L and C9R.

An upper end portion of the shock absorber unit 31 is connected to ashock absorber upper support portion 44 b of the shock absorber supportarm 44 through an upper connection shaft 44 c. A lower end portion ofthe shock absorber unit 31 is connected to the shock absorber lowersupport portion 23 e 5 of the lower arm 23 through a lower connectionshaft 23 e 6. A center axis C6 (stroke axis) of the damper 32 of theshock absorber unit 31 is provided. Referring to FIGS. 1, 2 and 3, thestroke axes C6L and C6R of the left and right shock absorber units 31Land 31R are disposed rearwardly of rear ends of the left and right frontwheels 2L and 2R.

On one end side in the radial direction of an upper end portion of theshock absorber unit 31, a holder 35 for holding a sub tank 34 of thedamper 32 is integrally provided. The sub tank 34 is provided in theform of a hollow cylinder which is located on an outer circumferenceside of an upper portion of the shock absorber unit 31 and is parallelto the stroke axis. In the present embodiment, the sub tank 34 of theshock absorber unit 31 in the state of being mounted to the vehicle bodyis disposed on a transversely outer side of a shock absorber main bodyincluding the damper 32 and the coil spring 33. Referring to FIGS. 4 and5, the sub tanks 34 of the left and right shock absorber units 31L and31R are on the outer circumference sides of the turning trajectories KLand KR of the left and right front wheels 2L and 2R, namely, on theradially outer sides of the circles centered on the kingpin axes C9L andC9R, as viewed in the axial direction of the steering shaft 12. Forexample, the sub tank 34 is a reservoir tank for the shock absorber unit31.

The shock absorber unit 31 strokes between the lower arm 23 and theshock absorber support arm 44 in response to an input of shock or thelike to the front wheel 2, thereby to absorb the shock or the likeinputted to the front wheel 2 and to attenuate vertical movements of thefront wheel 2. The shock absorber unit 31 is disposed forwardly of theengine 3 and rearwardly of the front wheel 2 in side view. Referring toFIGS. 4 and 5, the left and right shock absorber units 31L and 31R aredisposed within the transverse width of the engine 3, as viewed in theaxial direction of the steering shaft 12, and are disposed adjacent to afront portion of the engine 3.

The shock absorber support arm 44 is provided in an integral formobtained, for example, by integral forming of a metallic material. Theshock absorber support arm 44 integrally has the left and right armportions 44 aL and 44 aR at left and right outer sides of the baseportion 45, and integrally has the rear swing arm 46 upwardly of thebase portion 45. The left and right arm portions 44 aL and 44 aR areprovided at outer ends thereof with the shock absorber upper supportportions 44 b which support upper end portions of the left and rightshock absorber units 31L and 31R. On the shock absorber upper supportportions 44 b, upper end portions of the left and right shock absorberunits 31L and 31R are respectively supported through the upperconnection shafts 44 c which are parallel to the shock absorber swingshaft 45 a. The left and right arm portions 44 aL and 44 aR extend fromleft and right outer sides of the base portion 45 (supported on thevehicle body 1A in a swingable manner) while being displaced toward leftand right outer rear sides, respectively, and reach the shock absorberupper support portions 44 b while assuming a crank-like form as viewedin the axial direction of the steering shaft 12 as shown in FIG. 4. Thecenter axis of the shock absorber swing shaft 45 a (the swinging centerof the shock absorber support arms 44) is denoted by symbol C8.

Referring to FIGS. 4, 6 and 7, the steering link mechanism 17 isdisposed at a position spaced forward from the steering shaft 12. Thesteering link mechanism 17 includes: a front link member 15 extending inthe transverse direction; and left and right link members 14L and 14Rextending rearward from left and right end portions of the front linkmember 15. Each of base end portions 14 a as rear end portions of theleft and right link members 14L and 14R is connected to the link supportportion 9 c of the front suspension frame body 5 in a rotatable mannerthrough a rear link rotating shaft 14 c extending substantially inparallel to the kingpin axis C9 in side view. To front end portions ofthe left and right link members 14L and 14R, left and right end portionsof the front link member 15 are connected in a rotatable manner throughfront link rotating shafts 14 b parallel to the rear link rotatingshafts 14 c.

Under longitudinally intermediate portions of the left and right linkmembers 14L and 14R, inner rod connection portions 14 d for connectinginner end portions of the left and right tie rods 16L and 16R areprovided in a projecting form. Outer end portions of the left and righttie rods 16L and 16R are connected to the outer rod connection portions26 c of the left and right knuckle members 26L and 26R. Sphericalbearings 16 a and 16 b are provided respectively at the inner and outerend portions of the left and right tie rods 16L and 16R. The inner andouter end portions of the left and right tie rods 16L and 16R areconnected to the inner and outer rod connection portions 14 d and 26 cthrough these spherical bearings 16 a and 16 b by, for example, boltsinserted from the front side.

In one (in FIGS. 7(a) to 7(c), the left link member 14L) of the left andright link members 14L and 14R, a connection arm 14f for connecting afront end portion of the link rod 13 is provided in a projecting mannerat the base end portion 14 a supported by the front suspension framebody 5. Spherical bearings 13 a and 13 b are provided respectively atfront and rear end portions of the link rod 13. The front and rear endportions of the link rod 13 are connected to the connection arm 14 f andthe bottom bracket 12 a through these spherical bearings 13 a and 13 brespectively by, for example, bolts inserted from the upper side or thelower side.

The bottom bracket 12 a, the connection arm 14 f and the link rod 13constitute a substantially parallel link as viewed in the axialdirection of the steering shaft 12, and interlocks rotation of thesteering handlebar 11 with rotation of the left link member 14L. Inaddition, when the left link member 14L is rotated, the right linkmember 14R is also rotated through the front link member 15.

The steering link mechanism 17 exhibits an equivalent action to that ofan Ackerman mechanism. More specifically, when the left and right frontwheels 2L and 2R are steered through the steering link mechanism 17, thesteering angle of the front wheel 2 on the inner wheel side of the leftand right front wheels 2L and 2R becomes greater than the steering angleof the front wheel 2 on the outer wheel side.

For instance, as viewed in the axial direction of the steering shaft 12(see FIGS. 7(b) and 7(c)), the connection positions between the innerend portions of the left and right tie rods 16L and 16R and the innerrod connection portions 14d of the left and right link members 14L and14R are set at positions deviated from the axes of the left and rightlink members 14L and 14R, whereby the steering characteristics of theleft and right front wheels 2L and 2R can be changed. More specifically,as shown in FIGS. 7(b) and 7(c), as viewed in the axial direction of thesteering shaft 12, the connection positions between the inner endportions of the left and right tie rods 16L and 16R and the inner rodconnection portions 14 d of the left and right link members 14L and 14Rare located on the transversely inner sides of the axes of the left andright link members 14L and 14R. Therefore, the Ackerman percentage canbe set higher. More specifically, the steering angle of the front wheel2 on the inner wheel side of the left and right front wheels 2L and 2Rcan be set larger than the steering angle of the front wheel 2 on theouter wheel side. Consequently, desired turning characteristics can beobtained. The “Ackerman percentage” means a ratio concerning thesteering angles of the left and right front wheels 2L and 2R at the timeof turning (cornering).

In FIGS. 15(a) to 15(c), for convenience of explanation, there is showna case where the Ackerman percentage is 0, or where the connectionpositions between the inner end portions of the left and right tie rods16L and 16R and the inner rod connection portions 14 d of the left andright link members 14L and 14R are located on the axes of the left andright link members 14L and 14R as viewed in the axial direction of thesteering shaft 12.

As aforementioned, the cam 61 (first regulation member) is so formed asto reduce the turning angle of the front wheel 2L when the swingingangle about the swing axis C12L exceeds a predetermined angle.

Referring to FIGS. 14(a) and 15(a), when the left and right front wheels2L and 2R are steered to the left side through the steering linkmechanism 17 in a condition in which the vehicle body is upright, theupper edge portion 63 of the outer circumference 61 a and the roller 62a contact each other. See FIG. 14(a) and FIG. 15(a). By this, directcontact between the vehicle body 1A and the front wheels 2L and 2R isavoided.

When the left and right front wheels 2L and 2R are steered to the leftside through the steering link mechanism 17 in a state in which thevehicle body is banking to such an extend as not to reach full banking(a state of banking at a bank angle slightly shallower than that at fullbanking), the intermediate edge portion 65 located at the verticallyintermediate portion (boundary) between the upper edge portion 63 andthe lower edge portion 64 of the outer circumference 61 a and the roller62 a contact each other. See FIG. 14(b) and FIG. 15(b). Up to thispoint, the steering angle is constant at full steering.

When the left and right front wheels 2L and 2R are steered to the leftside through the steering link mechanism 17 in a substantially fullbanking state of the vehicle body, the lower edge portion 64 of theouter circumference 61 a and the roller 62 a contact each other. SeeFIG. 14(c) and FIG. 15(c). By this, the steering angle of the left frontwheel 2L is limited to a steering angle smaller than that at the fullsteering. In addition, the steering angle of the right front wheel 2R isalso limited similarly through the steering link mechanism 17.

In the present embodiment, in order to ensure that the steering anglesof the front wheels 2L and 2R are varied according to the roll angle(bank angle), the moving trajectory of the roller 62 ais set to be alongthe circular arc centered on the swing axis C12L, as viewed from thedirection along the swing axis C12L, in a range from an upright state ofthe vehicle body to a shallow bank angle. On the other hand, in a rangefrom the shallow bank angle to the full banking, the moving trajectoryof the roller 62 a is set to go toward a left lower side (the directionof arrow V1 in FIG. 15(c)) while gently curving toward the radiallyouter side of the circle centered on the swing axis C12L. It is to benoted that the configuration in which the steering angle is set constantat full steering up to an intermediate point in the course is notlimitative, and the steering angle may be regulated by varying the camprofile, for example, gradually varying the outer circumference 61 a ofthe cam 61.

As has been described above, in the above embodiment, the rolling typevehicle 1 which has the pair of left and right front wheels 2L and 2Rand in which the vehicle body 1A is capable of rolling includes thepairs of left and right upper arms 21 and lower arms 23 (arm members)which are supported in a swingable manner by the vehicle body 1A oninner sides in the transverse direction and which support the left andright front wheels 2L and 2R in a steerable manner on outer sides in thetransverse direction, respectively. As viewed from the direction alongthe axes C2 and C3 of the upper and lower roll shafts 22 and 24 (supportshafts) support the left and right upper arms 21 and lower arms 23 onthe vehicle body 1A. The base portions 21 a, 21 b, 23 a, and 23 b of theleft and right upper arms 21 and lower arms 23 are rotatably supportedon the vehicle body 1A side and overlap with each other. The center axisC11 (swinging center axis) of the base portions 21 aL and 21 bL of theleft upper arm 21L (left arm) and the center axis C12 (swinging centeraxis) of the base portions 21 aR and 21 bR of the right upper arm 21R(right arm), of the base portions 21 a, 21 b, 23 a, and 23 b of the leftand right upper arms 21 and lower arms 23, are out of alignment witheach other (do not coincide with each other).

Owing to this configuration wherein the base portions 21 a, 21 b, 23 a,and 23 b of the left and right upper arms 21 and lower arms 23 which arerotatably supported on the vehicle body 1A side overlap with each otherand wherein the center axis C11 of the base portions 21 aL and 21 bL ofthe left upper arm 21L and the center axis C12 of the base portions 21aR and 21 bR of the right upper arm 21R, of the base portions 21 a, 21b, 23 a, and 23 b of the left and right upper arms 21 and the lower arms23, are out of alignment with each other, as viewed from the directionalong the axes C2 and C3, it is ensured that the positions of the centeraxes C11 and C12 of the base portions of the left and right upper arms21L and 21R can be set more freely within a range in which the baseportions 21 a and 21 b of the upper arms 21 overlap with each other asviewed in the direction along the axis C2, as compared with the casewhere the center axis C11 of the base portions 21 aL and 21 bL of theleft upper arm 21L and the center axis C12 of the base portions 21 aRand 21 bR of the right upper arm 21 are coincident with each other asviewed from the direction along the axes C2 and C3. As a result, thelength of the left and right arms (the length of the left and rightupper arms 21L and 21R in the vehicle width direction) can be enlargedwhile enhancing the degree of freedom of layout.

In addition, in the above embodiment wherein the center axis C11 of theleft upper arm 21L is disposed on the right side of the longitudinallyextending vehicle body center axis CL whereas the center axis C12 of theright upper arm 21R is disposed on the left side of the longitudinallyextending vehicle body center line CL, the length of the left and rightarms can be enlarged effectively, as compared with the case where thecenter axis C11 of the left upper arm 21L is disposed on the left sideof the longitudinally extending vehicle body center line CL whereas thecenter axis C12 of the right upper arm 21R is disposed on the right sideof the longitudinally extending vehicle body center line CL. Further, itis possible to reduce the length of the upper arms 21 in the vehiclewidth direction (the whole width) and thus, to reduce the vehicle width,as compared with the case where the center axis C11 is disposed on theleft side of the longitudinally extending vehicle body center line CLwhereas the center axis C12 is disposed on the right side of thelongitudinally extending vehicle body center line CL.

In the above embodiment wherein the center axes C11 and C12 of thoseones of the left and right upper arms 21L and 21R (upper arms) and leftand right lower arms 23L and 23R (lower arms) which correspond to thegreater one of the distances L1 and L2 are out of alignment with eachother, as viewed from the direction along the axes C2 and C3, it isensured that a clearance can be secured between those ones of the leftand right upper arms 21L and 21R and the left and right lower arms 23Land 23R which are more liable to interfere with component partssurrounding the front wheels 2L and 2R at the time of swinging of thearms and the surrounding component parts. Consequently, interferenceamong vehicle component parts can be effectively avoided.

Further, in the above embodiment wherein the distance L2 for the lowerarms 23 is set smaller than the distance L1 for the upper arms 21, it iseasier to secure a minimum road clearance as compared with the casewhere the distance L2 for the lower arm 23 is set greater than thedistance L1 for the upper arms 21. In addition, with the center axes C11and C12 of the left and right upper arms 21L and 21R being set out ofalignment with each other as viewed from the direction along the axisC2, clearance can be secured between the left and right upper arms 21Land 21R liable to interfere with component parts surrounding the frontwheels 2L and 2R at the time of swinging of the arms and the surroundingcomponent parts. Therefore, interference among vehicle component partscan be obviated effectively. Consequently, interference among vehiclecomponent parts can be avoided effectively while securing a minimum roadclearance.

In the above embodiment wherein the base portions 21 aL and 21 bL of theleft upper arm 21L and the base portions 21 aR and 21 bR of the rightupper arm 21R are supported by the eccentric collars 50 fitted to thesame roll shaft 22 (support shaft), it is ensured that the length of theleft and right arms can be enlarged by just a required amount withoutcausing an increase in weight, as compared with the case where thenumber of swing shafts is increased by, for example, providing the swingshafts on the basis of each of the left upper arm 21L and the rightupper arm 21R.

It is to be noted that while the above embodiment has been described byshowing an example in which the actuator 41 and the shock absorbersupport arm 44 are interlocked with each other through an interlockmechanism such as the connection link 48, this is not restrictive. Forinstance, the actuator and the shock absorber support arm may bedisposed coaxially with each other.

A two-front-wheel suspension system 104 according to a modification ofthe embodiment will be described below, referring to FIGS. 16 and 17. InFIGS. 16 and 17, components equivalent to the components in the aboveembodiment are denoted by the same symbols as used above, and detaileddescriptions of them are omitted.

Referring to FIGS. 16 and 17, in the two-front-wheel suspension system104 according to the modification, at a rear portion of the actuator 41,there is provided a front swing arm 143 projecting upward and adapted toswing about the axis C7. The front swing arm 143 is fixed to the drivingshaft 41 a of the actuator 41 and swings about the axis C7. The frontswing arm 143 is opposed to a rear swing arm 146 of a shock absorbersupport arm 144 with a spacing therebetween along the axial direction ofthe actuator 41. More specifically, as viewed from the axis C8, a tipportion 143 b of the front swing arm 143 (a connection portion between aconnection device 147 and the front swing arm 143) is opposed to a tipportion 146 b of the rear swing arm 146 (a connection portion betweenthe connection device 147 and the rear swing arm 146) with an intervaltherebetween. At a connection portion 140 between the front swing arm143 and the rear swing arm 146, there is provided the connection device147 (load detection unit) which enables them to swing as one body. Theconnection device 147 functions also as a load detection unit whichdetects a load transmitted between the front and rear swing arms 143 and146.

The connection device 147 is, for example, in the form of a hollowcylinder parallel to the shock absorber swing shaft 45 a. Bolts 147 aand 147 b penetrating tip portions of the front and rear swing arms 143and 146 from the front side or the rear side are engaged to centralportions of front and rear ends of the connection device 147, wherebythe connection device 147 is fastened and fixed to the tip portions ofthe front and rear swing arms 143 and 146. The connection device 147incorporates therein a load sensor adapted to electrically detect a load(torque) about the shock absorber swing shaft 45 a which is generatedbetween the front and rear swing arms 143 and 146. A detected value ofthe load (torque) is inputted to an ECU (not shown) adapted to controlthe operation of the actuator 41.

The load about the shock absorber swing shaft 45 a which is generatedbetween the front and rear swing arms 143 and 146 is generated accordingto an operation resistance (torque) of the front swing arm 143 when theshock absorber support arm 144 is about to swing relative to theactuator 41 which is supported on the vehicle body side. Morespecifically, when the vehicle body rolls, a load about the shockabsorber swing shaft 45 a is generated between the front and rear swingarms 143 and 146, according to the operation resistance of the frontswing arm 143. The ECU controls the driving of the actuator 41 accordingto the detected value of the load. The swinging center (axis C7) of thefront swing arm 143 of the actuator 41 and the swinging center (axis C8)of the rear swing arm 146 of the shock absorber support arm 144 arecoaxially with each other, whereby an interlock mechanism between themis made simple and compact.

It is to be noted that the present invention is not limited to the aboveembodiment. For example, the application of the present invention is notlimited to a three-wheeled vehicle having left and right front wheelsand a single rear wheel, and the invention may be applied to afour-wheeled vehicle having left and right front wheels and left andright rear wheels.

The configuration in the above embodiment is mere an example of thepresent invention and various modifications are possible withoutdeparting from the spirit or scope of the present invention, such as byreplacing a component of the embodiment with a known component.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A rolling vehicle having a pair of left and rightfront wheels and having a vehicle body capable of rolling, the rollingtype vehicle comprising: a pair of left and right arm members swingablysupported on the vehicle body on inner sides in a transverse directionfor supporting the left and right front wheels in a steerable manner onouter sides in the transverse direction; wherein as viewed from adirection along an axis of a support shaft for supporting the left andright arm members on the vehicle body, the base portions of the left andright arm members which are rotatably supported on the vehicle body sideoverlap with each other, whereas a swinging center axis of the baseportion of the left arm and a swinging center axis of the base portionof the right arm, of the base portions of the left and right armmembers, are out of alignment with each other.
 2. The rolling vehicleaccording to claim 1, wherein the swinging center axis of the left armis disposed on the right side of a longitudinally extending vehicle bodycenter line, while the swinging center axis of the right arm is disposedon the left side of the longitudinally extending vehicle body centerline.
 3. The rolling vehicle according to claim 1, wherein the left andright arm members each include an upper arm and a lower arm; thedistance from an axle center of the front wheel to a transversely outerend portion of the upper arm and the distance from the axle center to atransversely outer end portion of the lower arm are different from eachother; and the swinging center axes of those ones of the upper arms andthe lower arms which correspond to the greater one of the distances aredeviated from each other in transverse direction, as viewed from adirection along the axis of the support shaft.
 4. The rolling vehicleaccording to claim 2, wherein the left and right arm members eachinclude an upper arm and a lower arm; the distance from an axle centerof the front wheel to a transversely outer end portion of the upper armand the distance from the axle center to a transversely outer endportion of the lower arm are different from each other; and the swingingcenter axes of those ones of the upper arms and the lower arms whichcorrespond to the greater one of the distances are deviated from eachother in transverse direction, as viewed from a direction along the axisof the support shaft.
 5. The rolling vehicle according to claim 3,wherein the distance for the lower arm is set smaller than the distancefor the upper arm; and the swinging center axes of the left and rightupper arms are out of alignment with each other, as viewed from adirection along the axis of the support shaft.
 6. The rolling vehicleaccording to claim 4, wherein the distance for the lower arm is setsmaller than the distance for the upper arm; and the swinging centeraxes of the left and right upper arms are out of alignment with eachother, as viewed from a direction along the axis of the support shaft.7. The rolling vehicle according to claim 1, wherein the base portion ofthe left arm and the base portion of the right arm are supported byeccentric collars fitted on the same support shaft.
 8. The rollingvehicle according to claim 2, wherein the base portion of the left armand the base portion of the right arm are supported by eccentric collarsfitted on the same support shaft.
 9. The rolling vehicle according toclaim 3, wherein the base portion of the left arm and the base portionof the right arm are supported by eccentric collars fitted on the samesupport shaft.
 10. The rolling vehicle according to claim 5, wherein thebase portion of the left arm and the base portion of the right arm aresupported by eccentric collars fitted on the same support shaft.
 11. Asuspension system for a vehicle comprising: a pair of left and right armmembers swingably supported on a vehicle body on inner sides in atransverse direction for supporting left and right front wheels in asteerable manner on outer sides in the transverse direction; wherein asviewed from a direction along an axis of a support shaft for supportingthe left and right arm members on the vehicle body, the base portions ofthe left and right arm members which are rotatably supported on thevehicle body side overlap with each other, whereas a swinging centeraxis of the base portion of the left arm and a swinging center axis ofthe base portion of the right arm, of the base portions of the left andright arm members, are out of alignment with each other.
 12. Thesuspension system for a vehicle according to claim 11, wherein theswinging center axis of the left arm is disposed on the right side of alongitudinally extending vehicle body center line, while the swingingcenter axis of the right arm is disposed on the left side of thelongitudinally extending vehicle body center line.
 13. The suspensionsystem for a vehicle according to claim 11, wherein the left and rightarm members each include an upper arm and a lower arm; the distance froman axle center of the front wheel to a transversely outer end portion ofthe upper arm and the distance from the axle center to a transverselyouter end portion of the lower arm are different from each other; andthe swinging center axes of those ones of the upper arms and the lowerarms which correspond to the greater one of the distances are deviatedfrom each other in transverse direction, as viewed from a directionalong the axis of the support shaft.
 14. The suspension system for avehicle according to claim 12, wherein the left and right arm memberseach include an upper arm and a lower arm; the distance from an axlecenter of the front wheel to a transversely outer end portion of theupper arm and the distance from the axle center to a transversely outerend portion of the lower arm are different from each other; and theswinging center axes of those ones of the upper arms and the lower armswhich correspond to the greater one of the distances are deviated fromeach other in transverse direction, as viewed from a direction along theaxis of the support shaft.
 15. The suspension system for a vehicleaccording to claim 13, wherein the distance for the lower arm is setsmaller than the distance for the upper arm; and the swinging centeraxes of the left and right upper arms are out of alignment with eachother, as viewed from a direction along the axis of the support shaft.16. The suspension system for a vehicle according to claim 14, whereinthe distance for the lower arm is set smaller than the distance for theupper arm; and the swinging center axes of the left and right upper armsare out of alignment with each other, as viewed from a direction alongthe axis of the support shaft.
 17. The suspension system for a vehicleaccording to claim 11, wherein the base portion of the left arm and thebase portion of the right arm are supported by eccentric collars fittedon the same support shaft.
 18. The suspension system for a vehicleaccording to claim 12, wherein the base portion of the left arm and thebase portion of the right arm are supported by eccentric collars fittedon the same support shaft.
 19. The suspension system for a vehicleaccording to claim 13, wherein the base portion of the left arm and thebase portion of the right arm are supported by eccentric collars fittedon the same support shaft.
 20. The suspension system for a vehicleaccording to claim 15, wherein the base portion of the left arm and thebase portion of the right arm are supported by eccentric collars fittedon the same support shaft.